Exhaust crossover mod question
 

'90 4runner 3.0, bone stock.

Gonna do the ISR mod, and maybe the airbox mod, and maybe either advance the timing to 11 or 12? or do the ECT sensor mod that advances/enriches.

My objectives: cheap, simple, slight improvement, maybe alleviate heat buildup.

I see occasional reference to an exhaust crossover mod, but I searched and can't seem to find anything on simple mods to stock exhaust system.

Is there such a thing?

I'm not interested in running without cats, or buying headers or cams or any other aftermarket hops.

Thanks for any help or links!!

the crossover mod uses block off plates to close the outlets on the stock manifolds and a header y-pipe to mount to the manifolds...if i remember right it was around $150ish to do..